George m



(No Model.)

G. M.'1VIOWBRAY.

MANUFAOTURB 0F PYROXYLINE. No. 350,498. Patented Oct. 12,1886.

UNITED lSTATES PATENT OFFICE.

GEORGE M. MOWBRAY, OF NORTH ADAMS, MASSACHUSETTS, ASSIGNOR TO y THEAMERICAN ZYLONITE COMPANY, OF NEW- YORK, N. Y.

MANUFACTURE OF PYROXYLINE.

SPECEFICATION forming part of Letters Patent No 350,498, dated October12, 1886K.

(No model.)

T0 all whom t may concern:

Be it known that l, GEORGE M. MOWBRAY, a citizen of the United States,residing at North Adams, in the county of Berkshire and State 0fMassachusetts, have invented new and useful Improvements in Manufactureof Pyroxyline, of which the following is a speciiication.

In the specification of a separate application, Case B, tiled of evendate herewith, setting forth a new process of restoring spent acid inthe manufacture of pyroXyline, reference is made to certain apparatusused, consisting, essentially, of, first, a turn-table and eightconverting-Vessels; second, acentrifugal machine; third, a spent-acidtank; fourth, a concentrated mixed-acids tank 5 fifth, abuilding-up-acids tank, and 6, a temperature-controlling coil.

Heretofore in the manufacture of pyroxyline it has been deemed necessaryto use vessels made of stoneware for the purpose of converting celluloseinto nitro-cellulose or pyroXyline. I have discovered that cast-ironvessels treated so asto diminish the proportion of carbon therein (by.exposure to continued'heating, surrounded by infusoria or ironperoxide) can be successfully used for this purpose, and that the actionof acids upon the metal forms a ferrie sulphate, which, being insolublein the mixed nitric and sulphuric acid used, does not injuriously affectthe product. I have also discovered that what is known as Bessemersteel, homogeneous metal,or mild steel, which of late years has beensuccessfully manufactured into boiler-plates, iron rails, and wire,practically resists the action of these acids,

slight formation of ferrie sulphate occurring,

that precipitates very slowly, owing to its specific gravity closelyapproximating` to that of the mixed acid specific gravity, 1.695 orthereabout, while gaseous nitrous-acid seems to interpose between metaland acid, preventing further action. This discovery enables me todispense with the operation of coating wrought-iron vessels withparaffine or acidresisting compounds as practiced heretofore.

By using irontubing and malleabley or cast iron stop-cocks of similarmetal I have succeeded in constructing a plant of metal throughout, thusavoiding the great expense of stoneware; also, the weekly parafiining ofwrought-iron vessels, materially improving the apparatus, and greatlysimplifying and cheapening the manufacture on a large scale. The easewith which large quantities of acid can be moved from a lower level toan upper, so as to thereafter avail of gravity, provided closed vesselsof large capacitysay to contain fteen to thirty thousand pounds of acid,say, of eleven hundred to twenty-two hundred gallons of watercapacity-could be obtained, rendered these discoveries the basis of theprocess describedv'in Application B, before referred to, and instead offlanged tanks with covers that can be lifted, which are necessary toenable the workmen to parafflne the ordinary wrought-iron boiler-plate,a man-hole suffices; indeed, the action of the acids is so trivial thatit would take many years of corrosive action to disable a vessel if ofthe ythickness of three-eighths of an inch. Further, by `surrounding theordinary sheet-iron drums in which glycerine has been imported with anelliptic ring and headblocks,.with adjusting-screw at one end, I need nostoragevessels for either nitric or sulphuric acid, substitutingtheseiron drums heretofore used only for transportation. On arrival Iplace one of them on platform-scales and take the gross weight, thenlock the platform-scales so that there is no vibration, and by means ofa rubber plug, F, Figs. 1, 2, and 3, which carries one tube reaching tobottom of drum and another tube that permits air to enter on the surfaceof the liquid, on allowing compressed air to enter the drum the contentsare lifted to the required level, while the elliptical link a,sustaining the pressure of the head of the drums, there is no injuriousstrain on the Weakest part of the drum. After thus emptying a drum ofits contents the tare is now taken and weight of acid noted.

For the process described in my aforesaidl Case B, consisting of theaddition of a certain proportion of concentrated mixed acids to acertain proportion of spent acid, we really need only three tanks, whosetotal contents need be less than fifty thousand pounds, in lieu ofthirty tanks, Snc., whose totalcapacity is described as amounting toseventeen hundred and fteen thousand pounds, the value of stock IOO ofacids in the one case being less than twelve hundred dollars,as againstforty thousand dollars. Such are the differences that will be found oncomparing my apparatus with that described in Patent No. 299,388, datedMay 27, 1884:, where it will be seen the following vessels aredescribed, but which are wholly unnecessary in my process, Case B, andare therefore excluded in this application.

The vessels described in before-mentioned patent, that my processenables me to dispense with, are two sulphuric-acid tanks, capacityforty thousand pounds each; two nitric-acid tanks, capacity twelvethousand pounds each; one weighing-tank; eight storage-tanks, eapacity`one hundred thousand pounds each; large weighing-tank' car and railwayfor moving same; five teinperature-regulating pots; one auxiliaryweighing-pot, making a total of twenty-one vessels dispensed with by mylesscomplicated process. Every unnecessary vessel is a disadvantage forthese reasons, that an extended surface tends to weaken the acid byabsorption of moisture, and the degradation of the acids is proportionedto the time and extent of metallic surface exposed, which, if ofwrought-iron, is imperfectlyprotected by what is termed acid-proofcoatings.77 The ability to turn out an equal quantity of product withthese vastly-disproportioned means, is attained by the discoveryreferred to in aforesaid Case B. I repeat here-viz., that the so-calledflock, instead of being as described fiock or iiocculent matter detachedfrom the fiber, is simply ferrie sulphate Fe;(SO which, being of nearlysame specific gravity as the normal standard acid mixture used forconversion, is slow to settle. Being insoluble in the concentrated acidsitl is innocuous during the process of nitration, but as it iscompletely soluble when diluted with water, disappears as soon as thepyroxyli ne is plunged into the washing-water.

I will now describe the vessels l use, and refer to the drawingsaccompanying this specification, in which Figure l is a side elevationof an apparatus embodying my invention; Figs. 2 and 3, detail views ofdrum, elliptic ring, and plug.

The subjoined letters of reference, with an- .nexed explanations anddescription of modus operandi, will enable any one skilled in the art toavail of my invention.

A, spent-acid tank B, building up-acids tank; C, temperaturecontrollingcoil; l), concentrated -acids tank; E, drum, in sit for emptying; N,`)latform-scales; A, waste-pipe from centrifugal machine to spent-acidtank A; B', delivery-pipe from spent-acid tank A to building-up acidtank B; C', delivery-pipe from concentrated-acid tank D to building acidtank L; D, delivery-pipe from drum E to concentrated-acids tank D; E',compressed-air inlet-pipe for admitting compressed air on surface ofcontents of a drum; F', concentratedacids-tank glass gage; G, building-up-aeids tank glass gage; H H', waste-plugs to tanks D and B,respectively; K L M, man-'holes to tanks A, B, and D; O, connecting-pipefrom building-np-acid tank B to coil C; IP, delivery-pipe andcontrolling stopway for conveying builtup-acid ofsuitabletemperature toreplenish nitrating vessels. The compressed-air pipes are Q, R, and S,and should be inserted in or near to the side of thc man-hole of tanksA, B, and D, while air-pipes 'll and U, of about threequarters of aninch in diameter with stopcocks to control same, should be inserted fromthe domes, respectively, of tanks B and D, terminating about six inchesfrom the bottom of tanks to serve as a means of agitating and thoroughlymixing the acids sentinto these tanks.

Z is the pressure gage for air-pressure.

V, W, and X are air and nitrous-gas outletpipes leading through main. Yto ventilation.

Eight nitrating-vcssels, iixed on a suit-able turn-table, are eachcharged willi from one hundred and fifty to one hundred and eighty kilosof normal standard mixed acid, so as to occupy about three fourths ofits capacity. Into each of these charged vessels, at intervals of threeand one-half minutes, the operator immerses thirteen hundred and twentyfive grams of tissue -paper strips or bleached-cotton fiber. By the tilne the eighth vessel is charged-say in about twenty-four and one-halt'minutes-the tissue-paper or cotton fiber will have been convertedinto pyroxyline, and must now be transferred to a centrifugal machine, m,which, `in from one to three minutes, separates five-sixths of itsadherent acid, which passes from said machinethrough pipe A intospent-acid tank A. One whole days accumulation of spent acid is moreaccurately restored for the succeeding days use than is possible byreturning the spent acid of one preceding nitration to anitratingivessel and adding one-fifth of that added spcnt-acids volumeof concentrated mixed acid, .j ust as it is easier to perform oneoperation of restoration at the termination of a days work, instead ofabout two hundred operations during the day on a smaller scale. For thisreason I prefer using a building-up-acid tank, B, instead of making theconverting-vessel serve a purpose similar to that which the tank Bserves-viz., receiving spent acid, also concentrated mixed acid-#thelatter in a proportion that,with the spent acid left over in theconverting-vessel, makes these acids from three differing` sourcessuitable for nitration. I therefore prefer that one days accumulation ofspent acid from the centrifugal machine m shall be made into what I havetermed building-up acid, to serve for the next days work in restoringthe spent acid left in the nitrating-vessels after each immersion to acondition suitable for converting cellulose into nitro-cellulose. t

Full and complete details of this process of nitration and restorationhaving been given in a separate application, Case B, filed of even IODIIO

350,498 l s Y date herewith, it only remains to describe the mode ofoperating the apparatus, referring to thedrawings accompanying thisspecification. l/Ve commence by supposing the spent-acid tank A containsthe accumulation of a days workings received through pipe A from thecentrifugal machine m. First, mark on gage G correctly indicating levelof acid in buildiug-up-acid tank B; then close stop-cock O, alsostop-cock q on pipe A', between the centrifugal machine and spent-acidtank A; open the compressed-air stop-cock h andthe spentacid servicestop-cock t'. rIlhe compressed air on the surface of the spent acidcauses it'to rise in the pipe B, which transfers it into the building-np -acid tank B. Now note how many inches of rise of level the'gage Gindie cates after transfer, say, sixty inches. (I

. level. Now open stop-cockoon pipe C.

defer details of charging concentrated mixed acid-tank D for thepresent.) Close stop-cocks q or pipe Al and Z on pipe Dh, and opencompressed-air cock j. Mark on gage F exact As soon as the gageGindicates twelve inches in- ,creased level beyond the sixty inchesbefore noted, close stop-cock o on pipe O, shut off compressed-airsupply by stop-cock T, and open compressed*air-supply cock k foragitation, also exhaust-exit r. It is better to defer the agitationuntil the mixturehas cooled down to about Fahrenheit. To prepare theconcentrated mixed acids for tank D, of which we have just described ashaving transferred twelve inches to tank B, we proceed as follows: Adrum of nitric acid of suitable strength is rolled onto aplatt'orm-scale and its gross weight marked down. Lock the scale-beam toprevent vibration, and harness onto the drum the elliptical iron ringa', adjusting t-he blocks a a so as to bear against the drums heads,tighteningthe same with the set-screw b. Remove the iron screw-plug thatcloses the drum, and insert the rubberplug F, with its iron pipe andcoupling, which must now be connected to the pipe D', that leads intothe concentrated mixed acid tank D. Connect, also, the curved small pipeE with compressed-air service, open stop cock Z, and take level of glassgage accurately, so as to ascertain how many inches of level areequivalent to a given weight of each acid as a checkin future work. Whencontents of drum have been transferred from the drum E to the tank D,remove the elliptic ring, head-blocks, rubber plug, audits attachments,drain drum, insert tightly the iron plug, ascertain tare of drum, deductsame from gross weight, and set down net contents of drum and compareweight with level of glass gage F', for purpose of estimaiingcontentswllen taking stock, Ste.

Having transferred, as above described, the contents of four or tivedrums of nitric acid of proper strength, as described in my aforesaidapplication, Case B, and noted accurately their net contents, nextcalculate the proportion of sulphuric acid of suitable strength', asdescribed in the aforesaid Case B, and having rolled out ready for t-hescale as many drums of sulphuric acid as are required tomake up with thenitric acid hereinbefore referred to, what I ha\'e termed concentratedmixed acid,77 proceed to wei gh and transfer precisely as beforedescribed A for the transfer of the nitric acid. In adding thesulphur-ic acid there should be sufficient time allowed'between eachdrum of sulphuric acid added for the mixed acids to cool, otherwise ifthe acids get overheated the tanks may suffer. By this method oftransfer one weighing suffices to check from the chemical factory, andfor the process, for in all further uses of these vacids volumetricmeasurement by the glass gages is practicable; and as all transfers takeplace in closed vessels, except to replenish the converting-vessels,there is avoidance of waste, and fumes do not harrass the workmen.

I do not limit my invention to anyone ofthe three varieties ofpyroxyline known as, iirst, gun-cotton; second, collodion, or solublepyroxyline, and third, xyloidine, as it is applicable to each of these,or a mixture of them, bya 9o increased or diminished strength of acids;nor do I confine myself to the exact proportions of acids set down inthis specification.

Having thus described my invention, what I claim is l. In themanufacture of pyroxyline, the use of steeled east-iron pots for holdingthe mixed acids in which the cellulose is immersed during the process ofconversion. 2. The use of homogeneous metal, otherwise called Bessemerprocess steel, plates for tanks to serve as containing-vessels for .themixed acids use d in the process of converting cellulose into nitrocellulose.

' 3. The use of homogeneous metal, otherwise called Bessemer processsteel,77 plates for receiving-tanks and lstorage-tanks of the mixedconcentratedand spent acids used in the process of converting celluloseinto nitro-cellulose.

4. The combination of a spent-acid tank, a building-up-acid tank, and aconcentratingacid tank with a temperature-regulating coil.

5. The elliptic ring with head-blocks 'and adj listing-screw, incombination with wroughtiron drum, substantially as described.

6. The perforated plug, in combination with the wrought-iron'drum andthe compressed-air inlet and liquid outlet, substantially as de-Vscribed.

In testimony whereof I affix my signature in presence of two witnesses.

GEO. M. MOWBRAY.

Vitnesses:

HARRY S. MOWBRAY, MERRITT T. WHITE.

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